White horehound (Marrubium vulgare) is a member of the mint family with small white flowers and downy, silver-green, and distinctly bitter leaves. It has been used as a cough and cold remedy since ancient Roman times [1] and appears in Anglo-Saxon manuscripts as a treatment for respiratory complaints [2].

Horehound is both an expectorant and a spasmolytic: it helps shift tough, sticky phlegm from the airways while simultaneously easing bronchial spasm [3]. Nicholas Culpeper noted its use for expectorating stubborn phlegm [4], and the late-nineteenth century north American Eclectic physicians noted its pronounced stimulant action on the laryngeal and bronchial mucous membranes [5]. Horehound is a common ingredient in throat lozenges, and it was the top-selling herbal product in the US market from 2013 to 2019 [6].
Horehound can help in conditions such as acute and chronic bronchitis, dry coughs, catarrh, sinusitis, laryngitis, whooping cough and asthma [7, 8]. It acts as an expectorant, spasmolytic, anti-inflammatory, and is mildly sedative [9].
As with most herbs, some cautions apply: horehound is contraindicated in pregnancy due to emmenagogue and potential abortifacient effects [10], and very large quantities may provoke arrhythmia or act as a mild laxative [1, 11].
Aside from that, for a herb that’s been soothing inflamed airways since antiquity, white horehound remains relatively underappreciated in modern practice and deserves a place in the modern dispensary.
References
- Balch PA, Bell S. Prescription for herbal healing. 2nd ed. Penguin; 2012.
- Watkins F, Pendry B, Corcoran O, Sanchez-Medina A. Anglo-Saxon pharmacopoeia revisited: a potential treasure in drug discovery. Drug Discov Today. 2011;16(23-24):1069–75.
- McIntyre A. The complete herbal tutor. Aeon Books; 2019.
- Culpeper N. Culpeper’s complete herbal. Foulsham & Company Limited; 1975.
- Felter HW, Lloyd JU. King’s American dispensatory [Internet]. 1898 [cited 2026 May 19]. Available from: https://www.henriettes-herb.com/eclectic/kings/marrubium.html
- Smith T, Majid F, Eckl V, Morton Reynolds C. Market report. HerbalGram. 2020;131:52–65
- Alfs M. 300 herbs: their indications and their contraindications. Aeon Books; 2022.
- Menzies-Trull C. Herbal medicine keys to physiomedicalism including pharmacopoeia. 3rd ed. Faculty of Physiomedical Herbal Medicine; 2022.
- Bone K, Mills S. Principles and practice of phytotherapy. 2nd ed. Elsevier Health Sciences; 2013.
- Aćimović M, Jeremić K, Salaj N, Gavarić N, Kiprovski B, Sikora V, et al. Marrubium vulgare L.: a phytochemical and pharmacological overview. Molecules. 2020;25(12):2898.
- Duke JA. Handbook of medicinal herbs. 2nd ed. CRC Press; 2002.
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